Such a load sensor is, for example, known from DE 33 25 945 A1 and is based on the principle that forces affecting the side of the optical fiber lead to deformations of the corresponding fiber sections. In the case of the known structure, the optical fiber is displayed on a periodically i.e., cyclically) shaped support structure so that, in the case of a load vertical to the fiber axis, a periodic deformation occurs. When the latter stands in correct proportion to the beat length of two of the modes contained in the optical fibers, the changes in pressure cause corresponding changes in the mode coupling. The known structure is, in other words, strongly dependent on the geometry of the support structure and, ultimately, on its coefficient of expansion in cases of temperature change. Constant interference is also caused by tensile strain, as for example, when such a sensor is laid in a road surface.